1. Field of the Invention
This invention relates to a mast elongating member configuration for a forklift truck, and more particularly to a cross-sectional configuration of a first outer-mast elongating or channel member along which a second inner-mast elongating member is guided to be raised and lowered.
2. Description of the Prior Art
In connection with forklift trucks of the type wherein outer-mast elongating or channel members are provided for guiding inner-mast elongate members to be raised or lowered, each first outer-mast channel member is usually formed generally U-shaped in cross-section. The thicknesses of two flanges of the first member are equal to each other. With such an outer-mast channel member configuration, the flexural rigidity of the first channel member in the forward and backward directions can be maintained; however, the tortional rigidity of the first member is relatively low. This causes shaking of a cargo when the forklift truck turns when the cargo is raised to a high position. This also lowers the loading efficiency and steerability of the forklift truck.